The present invention generally relates to a transport stream recording apparatus and a transport stream recording method, a transport stream reproducing apparatus and a transport stream reproducing method, and a program recording medium. For example, the present invention relates to a transport stream recording apparatus and a transport stream recording method, a transport stream reproducing apparatus and a transport stream reproducing method, and a program recording medium which are suitably for use in recording an MPEG video stream for example onto a data recording medium so that the recorded video stream can be reproduced in random access manner and in reproducing the MPEG video stream.
MPEG (Moving Picture Experts Group) 2 transport streams are used in the satellite digital broadcast and terrestrial digital broadcast in Japan, Europe, and the US. Namely, transport streams as digital broadcast waves are multiplexed in a time division manner with packetized MPEG video and audio streams corresponding to the video and audio signals of broadcast programs.
If these transport streams can be recorded in the form of digital signals on the side of receivers, users can repeatedly view programs without degradation in picture and sound qualities.
Further, recording transport streams onto random-accessible recording medium such as a hard disc and an optical disc can realize random access reproduction in which broadcast programs can be reproduced from any point of time specified by user.
In an MPEG video stream, I picture, B picture, and P picture are arranged appropriately. The decoding of B picture and P picture uses the image data decoded in the past, so that only I picture can become the reproduction start position of these three types of pictures. Therefore, when random access reproduction is executed from a user-specified reproduction start position, the I picture which is nearest the specified reproduction start position is searched and the reproduction is started with that I picture.
However, to search for the I picture nearest the specified reproduction start position from a recorded transport stream, MPEG video packets must be extracted from the transport stream to analyze the header and payload of each MPEG packet. These extraction and analysis take time, thereby presenting a problem that prompt random access reproduction in response to user specification cannot be realized.